Apple is offering advertising firms a way make large iAd buys that can be doled out to companies at a lower volume than what Apple sells directly. The idea is to make the service more approachable to advertisers that want to run smaller campaigns.

Apple's first big deal is with WPP's GroupM as part of a spending commitment for more than $1 million from its clients, The Wall Street Journal says. Fifty other iAd campaigns are said to be in the works.

A report about the change from Bloomberg earlier today suggested the company had cut its rates "by as much as 70 percent" to keep big advertisers from taking their ad dollars elsewhere. Apple contends that the pricing has not changed as part of the new deal-making approach.

What's the big reason for the selling change? Competition, Bloomberg suggested. Even before iAds, other companies offered advertising technologies that worked not just on iOS devices, but on Google's Android, and other smartphone operating systems. For a company looking for a more streamlined approach to get on multiple platforms, those alternatives represent a one-stop shop.

Apple introduced its iAds platform not only as a new source of revenue for the company, but also to help developers make money from their apps, even if the apps themselves are free. Its big feature at launch was letting people view and interact with advertisements without being jettisoned from the application, something that's the norm in Web advertising but can be jarring to users on mobile devices.

The platform began on applications designed for the iPhone and iPod Touch, and later expanded to work on the larger-screened iPad. Apple has also created an entire application to demonstrate its capabilities, as well as some of the existing campaigns on the service.

Clarification at 5:00 p.m. PT: This story has been updated throughout to clarify the way Apple is offering iAds to buyers.